The pie chart is one type of charts, and mainly consists of sectors, sector description texts (percentages or numbers), legend texts, legends and a title. At present, information is extracted from the pie chart completely by adopting an image processing technology, and the validity of an image processing method completely depends on the image quality of an image to be processed. If the image quality is high, the accuracy of information extraction is high, otherwise, the accuracy is low. In other words, the accuracy of information extraction from the pie chart cannot be guaranteed at present.